When operating equipment such as a home electric appliance or vehicle-mounted equipment, it is effective to perform a gesture operation by making a hand motion, which enables an operator to operate the equipment without using a remote control or without touching an operation panel. Further, in cases of operating equipment for digital signage or the like in a public facility or a factory, it is difficult to use touchscreens since it cannot be assumed that every operator has a remote control and many of display devices are large in size. Therefore, the gesture operation having the above-described feature is effective. In order to achieve such a gesture operation, images of the operator composed of a plurality of frames are captured with an image capturing device such as a camera, movement between the frames is detected and thus the gesture operation is judged, for example. However, this method has problems in that a gesture is easily misjudged in a circumstance where the background greatly changes, such as an in-car environment, and that it is difficult to distinguish between the gesture operation and an unintended motion by the operator.
To resolve these problems, there exists a technology that increases the accuracy of the gesture judgment by limiting a target region of the gesture operation judgment with reference to the position of the operator's face, judging a specified operation by the operator in regard to the limited region, judging whether or not the operation was performed continuously for a predetermined period, and thereby distinguishing between the gesture operation and a change in the background or between the gesture operation and an unintended motion by the operator (see Patent Reference 1, for example).